1. Field of The Invention
The invention herein pertains to application and control of coatings to yarn, yarn webs and the like in continuous processes. The method and apparatus described herein are particularly useful in the field of textile yarn coatings and in preparing cord webs for vehicle tire manufacturing.
2. Description Of The Prior Art And Objectives Of The Invention
Various types of coatings such as sizing are applied to textile yarns and must be carefully monitored during application. Weaving and other subsequent operations are greatly influenced by the amount of starch or other sizing components on the yarn. Also, the efficiency by which the fabric is woven severely affects the ultimate fabric cost. Thus, too little or too much sizing applied can affect both the convenience and economics of later processing operations while excess amounts of sizing result in higher chemical costs during manufacturing. As a result, various instruments have been developed in the past for controlling the sizing applied to yarn during continuous yarn processing procedures. Both off-line and on-line instruments have been used for measuring weight, elongation of yarn (stretch), and moisture (retention) in an effort to better control the coatings applied. While such prior art devices have met with limited success, they have not permitted coating applications generally to only vary in the single digit percentage range. With increased competition from foreign textile manufacturers who produce goods with relatively low labor costs, the present invention was conceived and one of its objectives is to provide a method and apparatus for controlling the coating of yarn which will insure a uniform application over an extended run and the most accurate amount of coating pick-up.
It is still another objective of the present invention to provide a method to control the coating of yarn in order to achieve a greater efficiency in weaving and subsequent yarn operations.
It is yet another objective of the present invention to provide apparatus for controlling the coating of yarn which includes a moisture monitor and elongation measure for more greater accuracy.
It is also another objective of the present invention to provide a method and apparatus for controlling the coating of tire cord webs during on-line processing without the necessity of stopping the web for measurements or for equipment adjustment purposes.
It is yet still another objective of the present invention to provide a method and apparatus for coating yarn which includes the use of nuclear density sensors, digital cameras for opacity measurements, moisture detectors, encoders for the measurement of yarn elongation and microprocessor circuitry for sizing application equipment control.
Various other advantages and benefits of the present invention will become apparent as the details of the invention are presented below.